Backup Ring Tapered Surface Reduces Shaft Insertion Load
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Solution Overview
Problem
Conventional carbon dioxide sealing devices fail to maintain effective sealing and prevent seal ring protrusion when subjected to high-pressure fluids due to increased shaft insertion load and faulty mounting, especially when the outer diameter of the backup ring is set equal to or larger than the housing diameter, leading to inadequate contact and reduced sealing functionality.
Innovation Solution
A carbon dioxide gas sealing device with a backup ring featuring a tapered surface that reduces insertion load by guiding the shaft without contacting the high-pressure side end surface, and a two-stage tapered shape to enhance sealing properties under high-pressure conditions, including a gap at the low-pressure side to allow radial directional component forces to compress and seal effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer diameter of the backup ring is set equal to or larger than the inner diameter of the housing to eliminate gaps and improve sealing, then the sealing function is improved, but the shaft insertion load increases significantly
Solution Approach 1:
The backup ring's peripheral surface is segmented into two functional zones: a tapered surface portion (first region) that contacts the housing during insertion to guide alignment and reduce insertion load, and a parallel surface portion (second region) that contacts the housing during operation to maintain sealing under pressure. This segmentation allows the backup ring to fulfill both insertion and sealing functions without requiring the entire surface to be tight-fitting.
Solution Approach 2:
Different regions of the backup ring are given different geometric properties: the tapered surface portion has a gradual inclination angle to facilitate easy insertion and alignment, while the parallel surface portion provides a tight fit for effective sealing. This local differentiation of geometric quality allows each region to optimize its specific function without compromising the other.
2Reliability
If the backup ring is designed with a tight fit to the housing to prevent seal ring protrusion under high pressure, then the prevention of protrusion is improved, but the shaft insertion becomes difficult due to increased insertion load
Solution Approach 1:
The backup ring's peripheral surface is divided into a tapered surface portion for insertion and a parallel surface portion for sealing. The tapered portion reduces insertion resistance by providing a gradual entry angle, while the parallel portion ensures tight contact during operation to prevent seal ring protrusion.
Solution Approach 2:
The tapered surface portion performs the preliminary action of guiding the shaft into correct alignment and facilitating easy insertion before the parallel surface portion engages to provide the sealing function. This preliminary guiding action ensures proper positioning before the sealing function is activated under pressure.
3Reliability
If the backup ring contacts the housing tightly from the beginning to ensure proper sealing function, then the sealing function is improved, but the backup ring may become inclined during insertion leading to faulty mounting
Solution Approach 1:
The peripheral surface is segmented into a tapered surface portion that provides gradual guidance during insertion and a parallel surface portion that ensures tight sealing contact during operation. This prevents inclination during insertion while maintaining sealing accuracy.
Solution Approach 2:
The tapered surface portion performs preliminary alignment and guidance during insertion, ensuring the backup ring is properly positioned before the parallel surface portion engages for sealing. This preliminary action prevents inclination and faulty mounting.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces shaft insertion load and maintains effective sealing by preventing seal ring protrusion and improving sealing functionality under high-pressure conditions, with a 90% reduction in insertion load and enhanced sealing properties, even at high temperatures and pressures.
Implementation Method 1
A carbon dioxide gas sealing device with a backup ring featuring a tapered surface that reduces insertion load by guiding the shaft
Implementation Method 2
when pressure of fluid is applied from the high pressure side, the backup ring is pressed toward the low pressure side from the high pressure side through the seal ring
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A carbon dioxide gas sealing enclosed device capable of reducing an inserted shaft load and ensuring the function of preventing protruding toward a low pressure side and the sealing function of a seal ring even if subject to high-pressure fluid. The carbon dioxide gas sealing enclosed device (1) comprises a seal ring (20) provided in amounting groove (10) having a tapered groove bottom (12) provided in a shaft (2), and a backup ring (30) positioned on a lower pressure side L of the seal ring and having a tapered portion (35) corresponding to the tapered groove bottom (12), a gap g being provided between the side wall surface (11) on the lower pressure side L of the mounting groove (10) and the side end surface (32) on the lower pressure side L of the backup ring (30) when a pressure is applied from a high pressure side H, wherein a tapered surface (36) that approaches the peripheral surface (3a) of a housing (3) from the side end surface (31) on the high pressure side H toward the lower pressure side L is provided on the peripheral surface (34) on the side opposite to the tapered portion (35) of the backup ring (30). In addition, the tapered portion (35) has two-stage tapers.